Sludge lancing operations are used in the commercial power industry to remove accumulations and deposits of debris and other matter, referred to as sludge, from between individual tubes in an arrangement of a group of tubes, i.e., a tube sheet bundle, in various power plant components, such as steam generators and heat exchangers of the shell-and-tube variety. The accumulation of sludge in between individual tubes in tube sheet bundles may result in reduced efficiencies of power plant components. Sludge accumulation can also result in mechanical impingement or damage to tubes and chemical degradation or corrosion of tube walls in such components. Failure of one or multiple tubes can result in a power plant being taken out of service to repair or replace damaged tubes.
Typically, sludge lancing is performed during a power plant outage or when particular equipment (e.g., a steam generator) is placed out of service. Sludge lancing involves directing a high pressure stream of water through a tube sheet bundle to remove accumulated sludge from between individual tubes.
In a conventional system, a nozzle is mounted or secured to a pipe or other structure to provide stability and to allow the nozzle to translate along a horizontal axis. The nozzle can translate along a vertical axis by raising or lowering the pipe on which the nozzle is mounted. Aligning the nozzle prior to initiating the lancing operation is typically attempted by spraying a stream of water through a tube sheet bundle and visually observing the steam of water as it exits the bundle. Once the nozzle is aligned, there is no disruption to the water stream itself. Aligning the nozzle is an iterative and time consuming process that involves spraying water through the nozzle, visually observing the stream of water as it travels through the tube sheet bundle, and manipulating the position of the nozzle until the stream of water exits the tube sheet bundle without disruption of the stream of water. As well, because the nozzles are typically oriented so that their spray patterns are in a horizontal plane, numerous passes are typically made with the vertical position of the nozzle changed on each pass.
Because current methods rely on visual alignment of the nozzle, as described above, lancing sludge from between tubes (i.e., sludge lancing) is generally performed with the nozzle positioned 90° with respect to the tube sheet bundle, i.e., “head-on” to tube sheet bundle. However, it is often desirable to direct the stream of water from the nozzles at angles other than 90° in order to remove additional sludge that cannot be reached at 90°.
The present invention recognizes and addresses the foregoing considerations, and others, of prior art constructions and methods.